Internally cooled turbine blades may include passages within the blade. These hollow blades may be cast. In casting hollow gas turbine engine blades having internal cooling passageways, a fired ceramic core is positioned in a ceramic investment shell mold to form internal cooling passageways in the cast airfoil. The fired ceramic core used in investment casting of hollow airfoils typically has an airfoil-shaped region with a thin cross-section leading edge region and trailing edge region. Between the leading and trailing edge regions, the core may include elongated and other shaped openings so as to form multiple internal walls, pedestals, turbulators, ribs, and similar features separating and/or residing in cooling passageways in the cast airfoil.
U.S. Pat. No. 8,118,553 to George Liang, describes a cooling system for a turbine airfoil of a turbine engine having dual serpentine cooling channels, an inward serpentine cooling channel and an outward serpentine cooling channel, positioned within the airfoil. The inward serpentine cooling channel may receive cooling fluids from a cooling supply system through the root and exhaust cooling fluids to the outward serpentine cooling channel at the leading edge. The outward serpentine cooling channel may pass the cooling fluids through the outward portion of the serpentine cooling channel and exhaust the cooling fluids through the trailing edge of the airfoil. Such configuration yields a better creep capability for the blade.
The present disclosure is directed toward overcoming one or more of the problems discovered by the inventors.